Boiler feed water control



July 9, 1940.

J. A. CAMPBELL BOILER FEED WATER CONTROL Filed July 22, 1938 2 Sheets-Sheet l lllvenior'. Julian fl. az z bea 427027185,

J y 1940. J. A. CAMPBELL BOILER FEED WATER CONTROL Filed July 22, 1938 2.Sheets-Sheet 2 Patented July 9, 1940 UNKTED STATES 2,207,214 BOILER FEED WATER CONTROL Julian A. Campbell, Long Beach, oalif. Application July 22, 1938, SerialNo. 220,719 14 Claims. (01. i22- -1451.1'

This invention relates generally to liquid level control systems and to improvements in a type of thermally responsive regulating apparatus adapted particularly to level control of heated liquids. As herein shown and described, the invention is embodied in regulating apparatus for controlling the supply of water to boilers in accordance with variations in the water level. It will be understood however that the invention 1:0 broadly contemplates various specific forms of the apparatus adaptable to different situations involving liquid level control, and that the boiler feed water regulator herein described is to be. regarded merely as illustrative of the invention '15 in a typical and preferred form.

In its general construction, the present regulator comprises a pair of convergent elongated members, one of which is a tube, connected together at their convergent ends and suitably anchored at their opposite ends to a support. A tubular member is connected at its upper and lower ends to the steam and water chambers, respectively, of the boiler, and is disposed in an inclined position with relation to the boiler water level such that normally the water stands within the tube at a level intermediate its ends, and preferably at the central portion of the tube. Opposite end portions of the tube are heated to diflerential temperatures, the upper portion of the tube communicating with the boiler steam space and being maintained at relatively high temperature, and the lower portion of the tube connecting with the boiler water chamber and being cooled to relatively lower temperature. As the boiler water level changes, the temperature difierential at the opposite end portions of the tube changes due to the rise or fall, as the case may be, of the water level therein, with the result that the tube longitudinally expands or no contracts. The efiect of expansion or contraction of the tube is to cause the interconnected convergent ends of the members to move laterally, the degree of movement depending upon the dimensions and arrangement of the members, as well as the extent of expansion or contraction of the tube. The boiler feed water control valve is operated in accordance with the lateral end movement of the members, the valve being closed by movement of the members resulting from a rise of the water level in the tube above normal level, and opened by end movement of the members resulting from a drop of the water level in the tube below normal.-

One object of the invention is to provide means for maintaining increased temperature difler- 'bodiments of the invention.

entials between .the upper and lower portions. of the inclined tube. above and below the water level, and in so. doing to increase the sensitivity and responsiveness of the regulator to changes in thewater level. This object is accomplished by either or both of two improved features, one of which consists in the provision of means .for suitably cooling the lower portion of the tube below the water level, as by increasing itsheat radiating surfacearea. Thus, for example, by providing the lower portion only of the .tube with heat radiating fins, I am able to .maintain the water filled section of the. tube at a temperature considerably below the boiler water and steam temperatures, and thereby substantially increase 1 the temperature differential between the upper and lower portions of the tube.

This temperature differential is further increased by preventing the tube contained water frombecoming heated by condensate draining 420 from the upper section of thetube and its connection with the boiler steam chamber. In accordance withthe invention,'provision is made for removing and by-passing such condensate around thelower section of the tube and thereby 4'25 preventing the water therein from) becoming heated by the higher temperature condensate Another feature of the invention is the provision of an auxiliary control which is also responsive ;to changes in the boiler water level and no which operates to increase the sensitiveness and range of responsiveness of the main regulator assembly as described above. Additional features have to do with improved signal systems forindicating abnormaly high and low boiler water 5 levels. r

All the various objects and features of them- .vention referred to in the foregoing, as Well as various additional details, will be explained to better advantage in the following detailed ,de- 21, scription of certain typical and illustrativeem- Throughout the description, reference is had to the acompanying drawings in which:

Fig. 1 is a general view showing one form of regulator embodying the invention;

Figsp2 and 3 are fragmentary enlarged sections taken on lines 22 and 3-3 of Fig. 1;

, Fig. 4 is a view similar to Fig. 1 showing a variational form of the invention;

Fig. 5 is a fragmentary vertical section on line 55 of Fig. 4;

Fig. 6 is a cross section on line 6-6 of Fig. 4;

Fig. '7 is a fragmentary section on line 1-1 of Fig. 1.

Referring first to Fig. 1, the regulator generally indicated at H] is shown to be connected with valve II in the feed water supply line |2 leading to the boiler, the wall of which is conventionally indicated at. I3. It will be understood of course that the regulator may be applied to any suitable type of boiler. For the purpose of explaining the invention it will sufiice to refer to the regulator as being so positioned with relation to the normal water level L of the boiler as to enable the regulator to operate the valve H in response to variations in the liquid level, all as will be fully explained hereinafter.

The regulator l0 may be regarded generally as comprising a pair of elongated convergent members l4 and I5 connected at their outer ends by casting H5 or other suitable means, and pivotally mounted at their divergent ends on a stationary support H. The regulator member l5 comprises an inclined tube made of material, such as brass, having a suitable predetermined coefficient of expansion, the lower end of the tube being connected with the water chamber of the boiler by pipe l8, and the tube being positioned at an elevation such that normally the water stands in the tube at a level L, corresponding to the normal boiler water lever L, at substantially the longitudinal center of the tube. The member l4 may be of any suitable form, and is shown typically as comprising a solid forked steel rod.

The tube I5 is pivotally connected to the support H by a casting l9 having a hollow end portion I90, in which the tube and pipe l8 are threaded, and an opposite bifurcated end portion 20 pivotally attached to the support web |'|a by bolt 2|. The forked rod I4 is attached to the support by a yoke 22 having a bifurcated portion 22a connected with the support |'|a by bolt 23. The effective length of rod l4 relative to tube I5 is adjustable by means of nuts 24 on the threaded extension Ma. of the rod into which the branches I40 and hid of the rod merge, received within the yoke 22. The elevation of members l4 and i5 also is variable by providing the support web l'la with a vertical series of suitably spaced holes 25 through which bolts 2| and 23 may be inserted.

The outer end of tube I5 is threaded at 2'! into a hollow casting IE to which the ends of branches Me and M12 of the forked rod l4 are attached at 28 as shown in Fig. '7. The connections at 28 comprise tapered or frustro conical lugs received within correspondingly tapered bores 9| in the rod arms, the latter being held to the lugs by screws 92 tightened against washers 93. This type of connection between the rod and casting is of particular advantage in that the tapered engagement between the lugs and rod bores effectively prevents looseness and lost motion between the parts. upper portion of tube l5 above the water level therein communicate with the steam chamber of the boiler by a pipe or flexible conduit 29 connected at 30 into the side of the casting. Thus with tube l5 cormnunicating at its upper end with the boiler steam chamber and at its lower end with the water space in the boiler, the level L at which the water stands in the tube will at all times correspond with the water level L in the boiler, and the two levels will vary correspondingly and simultaneously.

Being connected with the steam chamber, the upper portion of tube l5 above the liquid level conversely when the water level drops.

The casting l6 and the therein is heated to a higher temperature than the lower portion of the tube, since the latter is cooled below the boiler water temperature due to heat radiation from the tube. It follows that as the water level rises or falls, the tube longitudinally contracts or expands by reason of the exposure of a lesser length of the tube to the steam temperature and a greater length to the water temperature when the water level rises, or The length of rod l4 remaining fixed, longitudinal contraction or expansion of the tube l5 produces lateral (vertical) movement of the interconnected ends of the members, the extent of such movement being determined by various factors including the degree of contraction or expansion of the tube, length of the members, and their angularity. The casting I6 is operatively connected to the feed water control valve H by an adjustable length push rod 3| attached at its upper end to the casting lug 32 and at its lower end to the valve operating lever 33.

Assuming the boiler water level to rise above normal, the accompanying rise of the water level L in tube I5 causes the latter to contract longitudinally, and the resulting downward deflection of the interconnected ends of the members depresses rod 3| to close the valve II and restrict the feed supply until the boiler water level drops to normal. Conversely, when the boiler water level falls below normal, the exposure of an increasing length of the tube I5 to the steam temperature causes the tube to expand and rod 3| to be moved upwardly to open the valve II and increase the rate of feed water supply.

One important object of the invention is to increase the normal temperature differential between the upper and lower portions of the tube l5 exposed to the steam and water respectively, and to increase the responsiveness or sensitivity of the tube to relatively small changes in the water level. Broadly speaking, this object is accomplished by providing means for cooling the lower portion of the tube below the water level, to a greater degree than the cooling that would result from heat radiation from a cylindric surface of the tube. While in the broad aspects of the invention this may be accomplished by any suitable means, I preferably provide the lower portion of the tube with increased heat radiating surface area, and relatively greater radiating surface area than that of the section of the tube above the water level. Relatively, therefore, heat radiation from the upper portion of the tube is reduced, to maintain its temperature comparatively high, while heat radiation from the lower portion of the tube is increased so as to cool that portion and increase the temperature differential between the steam and water containing sections of the tube,

As typical means for increasing heat radiation from the water containing portion of the tube, the latter is shown to be provided with a series of annular fins 34 which preferably are extended from the casting H! to substantially a point 35 of intersection between the normal water level L and the top wall of the tube. The annularly formed fins 34 have the combined advantages of affording greatly increased heat radiating surf-ace area, and permitting free expansion or contraction of the finned portion of the tube without interference by or distortion of the fins.

As an additional feature having also for its object to maintain maximum temperature differentials between the upper and lower portions of the tube, I provide suitable means for preventing water condensate from draining from pipe 29 and the upper portion of the tube above the level L, into the water standing in the tube, and thereby avoid heating the water and lower portion of the'tube which would result from the condensate being permitted todrain into it. Condensate formed in pipe 29 is permitted to drain into the bottom chamber 36 of casting I6, see Fig. 2, and is .thence drained through a flexible or light weight tube 31 connecting at 38 with the bottom of the chamber, into casting I9 through the connection at 39, see Fig. 3. In this manner the condensate from pipe 29 is caused to entirely bypass the tube I5. Tube 31 is also connected-at 40 into the bottom of coupling 4| in tube I5 somewhat above the normal water level L, so that condensate forming in the upper portion of the tube above the coupling, drains through the connection 40 into tube 31, instead of draining directly into the liquid in the bottom of tube I5.

Another feature of the invention is the provision of a signaling means operated by predetermined lateral movements of the members I4 and I5, whereby audible or visual indications are given when the boiler water reaches predee termined or excessive high or low levels. In the form of the invention shown in Fig. 1, the signal system, generally indicated at 42, includes a steam whistle 43 which blows automatically at predetermined high or lowwater levels. Steam supply to the whistle through line 54 connecting with the boiler steam chamber is controlled by a valve 45 operated by rod 4t supported on bracket 41 fixed to a suitable standard .8, the rod normally being pressed upwardly to close the valve by coil spring 49. The rod is adapted to be depressed against the resistance of spring is to open the valve by either of levers or 5|, the former being pivotally mounted at 52 on a stationary bracket 53, and lever 5I being pivoted'at 54 on the standard 48. Lever 5| is connected with lug 55 on casting I6 by an adjustable link or turnbuckle 56, the upper end of which is connected with lever 50 by coil spring 51.

Rod 46 carries a pair of nuts 58 and 59 which may be vertically and independently adjusted to cause valve 45 to open and blow the whistle at predetermined limits of movement of casting I5, and consequently predetermined high and low water levels. When the boiler water level drops to a dangerously low level, the resultant upward movement of casting I6 and link 56 swingslever 5I down against nut 59, depressing rod 46 and opening the valve 45 to give the signal. Similarly, when the boiler water reaches an excessively high level, the resultant downward movement of the casting l6 and rod 56 causes the spring 51 to pull lever 50 down against nut 58 to open the valve and blow the whistle,

Figs. 4 to 6 illustrate a variational form of the invention which is essentially similar to the first described embodiment, but includes an additional feature in the provision of a mechanism which also is responsive to variations in the water level, for increasing the range of movement of the valve operating regulator and its responsiveness to variations in the liquid level. In Fig. 4, the regulator assembly generally indicated at 69 is similar to the first described regulator I0, and the corresponding parts are given the same reference characters. The divergent ends of the members I4 and 15 are connected to a movable support 6 I, shaped in cross section as shown in Fig. 6 and pivotally suspended from shaft 62., see Fig. 5

supported by a pair o'fstandards 63 having suitable braces 64 extending to the base .65.of the frame structure. Support 6| is pivotally attached at 66 tothe upper end of an inclined tube 61 of. composition similar to tube I5, and pivotally mounted at its lower end 68 on a suitable support '69. Like tube I5, the lower end of tube 67 is connected by pipe 10 with the water space in the boiler, while the upper end of the tube is connected by way of pipe H with pipe 29 and therefore with the boiler steam chamber. The point of connection at 66 between the upper end of the tube 61 and the supporting member BI, is made vertically adjustable by providing the supholes 12. The bifurcated end 13 of coupling "M is attached to plate II by a bolt extending through one of the holes I2, As will be apparent, the connection at 68 between the lower end of the tube and support 69 is similarly adjustable.

Tube 61, like tube I5, is positioned relative to the normalboiler water level L such that the water normally stands in the tube at a level L" centrally intermediate its ends. As will be understood without the necessity forspeciiic illustra tion and more detailed description, the lower portion of tube 6'! may if desiredbe provided with heat radiating fins, and means for preventing the drainage of condensateinto the water contained in the tube, as shown and previously described with reference to Fig. 1. Variations in the boiler water level produces simultaneous changes in the water levels in tubes I5 and t'l, causing the tubes to coincidentally expand or contract. Expansion and contraction of tube I5 produces vertical movement of the casting I6 relative to'support BI, whereas expansion and contraction of tube 61 pivotally moves the support BI on shaft 62 and bodily moves members I4 and I5 so as to increase their lateral end movement at casting I6 in the same direction as the movement resulting from expansion and contraction of tube I5. Thus the expansive and con tractive efiect of tube 61 is to increase the range or extent of movement of the interconnected ends of members I4 and I5 in response to changes in the water level, and generally to increase the sensitiveness of the apparatus in response to given variationsin the water level.

In Fig. 4 I show a variational form of signaling system, generally indicated at I5, which operates to give visual indications when the boiler water reaches predetermined high and low levels. Rod 16 attached to casting I6 by bifurcated link]? carries a pair of arms I8 and I9 adapted to close the normally open switches 80 and BI in the electric circuits of difierent colored lamps 82 and 83. As a result of predetermined upward movement of rods I6, arm 18 closes the switch 90 to illuminate lamp 82, indicating dangerously low boiler water level. Similarly predetermined downwardmovement of rod I6 causes arm It to close the switch 8| and illuminate lamp 533 to indicate excessively high boiler water level.

I claim:

1. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, control means operated by longitudinal expansion and contraction of the tube, means connecting the lower portion of said tube with the liquid space'in said chamber and a pipe connecting the upper portion of said tube with the vapor space in said chamber, so that liquid stands in the tube at a level intermediate its ends, and means for drawing'liquid condensate from an intermediate pointin said tube above the liquid level therein.

2. Apparatusfor controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, control means operated by longitudinal expansion and contraction of the tube, means connecting the lower portion of said tube with the liquid space in said chamber and a pipe connecting the upper portion of said tube with the vapor space in said chamber, so that liquid stands in the tube at a level intermediate its ends, and means for draining liquid condensate from an intermediate point in said tube above the liquid level therein, into said means connecting the lower portion of the tube with the space in said chamber.

3. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, control means operated by longitudinal expansion and contraction of the tube, means connecting the lower portion of said tube with the liquid space in said chamber and a pipe connecting the upper portion of said tube with the vapor space in said chamber, so that liquid stands in the tube at a level intermediate its ends, a conduit extending longitudinally below said tube and communicating with said means connecting the lower portion of the tube with the liquid space in said chamber, and means for draining condensate into said conduit from an intermediate point in said tube above the liquid level therein.

4. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, control means operated. by longitudinal expansion and contraction of the tube, means connecting the lower portion of said tube with the liquid space in said chamber and a pipe connecting the upper portion of said tube with the vapor space in said chamber, so that liquid stands in the tube at a level intermediate its ends, a conduit extending longitudinally below said tube and communicating with said means connecting the lower portion of the tube with the liquid space in said chamber, means for draining condensate from said pipe into said conduit, and means for draining condensate into said conduit from an intermediate point in said tube above the liquid level therein.

5. Apparatus for controlling the level of heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclined tube, control means operated by longitudinal expansion and contraction of the tube, means connecting the lower portion of said tube with the liquid space in said chamber and a pipe connecting the upper portion of said tube with the vapor space in said chamber, so that liquid stands in the tube at a level intermediate its ends, means forming a chamber connected to said pipe and the upper end of said tube, and a conduit connected to the lower portion of said chamber and serving to drain off condensate entering the chamber from said pipe.

6. Apparatus for controlling the level of heated liquid in a chamber, comprising'an elongated inclined tube, means connecting the tube with said chamber so that liquid stands in. the tube intermediate its ends, a movable support for said tube, control means connected to one end of saidtube and operated by longitudinal expansion and contraction of the tube resulting from changes of the liquid level in said chamber, and means responsive to changes of said liquid level for moving said support and bodily moving said tube to increase the degree of movement of said end of the tube for a given change of liquid level in said chamber.

7. Apparatus for controlling the level of heated liquid in a chamber, comprising an elongated inclined tube, means connecting the tube with said chamber so that liquid stands in the tube intermediate its ends, a movable support for said tube, control means connected to one end of said tube and operated by longitudinal expansion and contraction of the tube resulting from changes of the liquid level in said chamber, and a second inclined tube connected to said support and communicating with said chamber so as to be responsive to changes of the liquid level therein and move said support to increase the degree of movement of said end of the first mentioned tube for a given change of liquid level in said chamher.

8. Apparatus for controlling the level of heated liquid contained in a chamber, comprising a pair of convergent elongated members, one of which is an inclined tube, connected together at their convergent ends, means connecting the tube with said chamber sothat the liquid stands in the tube intermediate its ends, a movable support, means for anchoring said members at their divergent ends to said support whereby longitudinal expansion and contraction of said tube resulting from changes of the liquid level in said chamber causes the connected ends of said members to move laterally, and means responsive to changes of the liquid level in said chamber for moving said support to increase the degree of movement of the convergent ends of said members resulting from said liquid level changes.

9. Apparatus for controlling the level of heated liquid contained in a chamber, comprising a pair of convergent elongated members, one oi which is an inclined tube, connected together at their convergent ends, means connecting the tube with said chamber so that the liquid stands in the tube intermediate its ends, a movable support, means for pivotally mounting said support, means for anchoring said members at their divergent ends to said support whereby longitudinal expansion and contraction of said tube resulting from changes of the liquid level in said chamber causes the connected ends of said members to move laterally, and means responsive to changes of the liquid level in said chamber for pivotally moving said support to increase the degree of movement of the convergent ends of said members resulting from said liquid level changes.

10. Apparatus for controlling the level of heated liquid contained in a chamber, comprising a pair of convergent elongated members, one of which is an inclined tube, connected together at their convergent ends, means connecting the tube with said chamber so that the liquid stands in the tube intermediate its ends, a movable support, means for anchoring said members at their divergent ends to said support whereby longitudinal expansion and contraction of said tube resulting from changes of the liquid level in said chamber causes the connected ends of said members to move laterally, an inclined pipe communicating with said chamber so that the liquid stands in said pipe at a level intermediate its ends, and means connecting the pipe with said support whereby expansion and contraction of the pipe resulting from changes of the liquid level moves the support to increase the, degree of movement of the convergent ends of said members caused by said liquid changes.

11. Apparatus for controlling the level of heated liquid contained in a chamber, comprising a pair of convergent elongated members, one of which is an inclined tube, connected together at their convergent ends, means connecting the tube with said chamber so that the liquid stands in the tube intermediate its ends, a movable support, means for anchoring said members at their divergent ends to said support whereby longitudinal expansion and contraction of said tube resulting from changes of the liquid level in said chamber causes the connected ends of said members to move laterally, an inclined pipe communicating with said chamber so that the liquid stands in said pipe at a level intermediate its ends, means connecting the upper portions of said tube and pipe, and means connecting the pipe with said support whereby expansion and contraction of the pipe resulting from changes in the liquid level moves the support to increase the degree of movement of the convergent ends of said members caused by said liquid level changes.

12. Apparatus for controlling the level of heated liquid contained in a chamber, comprising a-pair of convergent elongated members, one of which is an inclined tube, connected together at their convergent ends, means connecting the tube with said chamber so that the liquid stands in the tube intermediate its ends, means for anchoring said members at their divergent ends whereby longitudinal expansion and contraction of said tube causes the connected ends of said members to move laterally, a whistle connected to a vapor space in said chamber, valve means controlling the flow of steam to said whistle, and means connected to the convergent ends of said members and operating said valve means to blow the Whistle upon lateral movement of said ends to heated liquid contained in a chamber having a vapor space above the liquid level therein, comprising an inclinedtube, control means operated by longitudinal expansion and contraction of the tube, means connecting the lower portion of said tube with the liquid space in said chamber and a pipe connecting the upper portion of said tube with the vapor space in said chamber, so that liquid stands in the tube at a level intermediate its ends, said pipe having an upwardly extending portion beyond the upper end of the tube, a fitting interconnecting said pipe with the upper end of said tube and receiving liquid condensate draining clown said upwardly extending portion of the pipe, and means communicating with the liquid space in said chamber for draining said condensate from said fitting to prevent the condensate from entering the tube.

14. Apparatus for controlling the level of heated liquid contained in a' chamber having a vapor space above the liquid level therein, comprising an inclined tube, control means operated by longitudinal expansion and contraction of the tube, means connecting the lower portion of said tube with the liquid space in said chamber and a pipe connecting the upper portion of saidtube with the vapor spacein said chamber, so that liquid stands in the tube at a level intermediate its ends, said pipe having an upwardly extending portion beyond the upper end of the tube, a fitting interconnecting said pipe with the upper end of said tube and receiving liquid condensate draining down said upwardly extending portion of the pipe, and a condensate drain conduit extending longitudinally below-said tube and interconnecting said fitting and said means that connects the lower portion of the tube with the liquid space in said chamber.

. JULIAN A. CAMPBELL. 

